The RA33 recording card was produced in August 1977 by the Biological Records Centre for the Hoverfly Recording Scheme. A sizeable proportion of the records collated by the scheme during the period in the run up to the published atlas were submitted on these cards.

It was intended that a seperate card was filled in for each site visit. Like most BRC cards, RA33 has a header section in which the observer filled in details of the visit: date, grid reference, location name, etc. Most of the card then consisted of a species list (based on the Kloet & Hincks, 1976, checklist). The species observed during the site visit were indicated by putting a line through their names on this list.

Each name in the checklist on the card is prefixed by a number. BRC has a system of numbering species using a 4-digit number to indicate the group (in this case Diptera, Cyclorapha 6482 - shown at the top-right corner on the front of the card) and a 4-digit number of which the first two digits represent the genus and the other two digits the species within the genus. Thus Anasimyia is genus 1 on this card and its three species are numbered "101", "102" and "103". When data was entered from cards by BRC, typing these numbers was the method of inputting species and many other people have used BRC numbers to identify the species in their own databases or date entry spreadsheets.

Unfortunately the RA33 card has an error in the numbering as the genera: Chrysotoxum and Criorhina are both numbered 12 (the numbers for Criorhina should start "13"), so Chrysotoxum arcuatum and Criorhina asilica have the same number (1201), as do Chrysotoxum bicinctum and Criorhina berberina (1202), Chrysotoxum cautum and Criorhina floccosa (1203) and Chrysotoxum elegans and Criorhina rannunculi (1204). This has caused quite a bit of confusion and, although the records for which the Scheme received cards, were all checked and corrected, it is not unlikley that some Criorhina records have ended up asssigned to Chrysotoxum.

Because the names listed on RA33 are from an old checklist and there have been many subsequent name changes, there are a number of problems.

The genus Paragus was extensively revised and it is no longer clear what is meant by the name Paragus finitimus. This cannot be associated with any of the species as we currently understand this. I don't think we have actually seen any records claimed of this species, but they would just have been ignored!

The card did not attempt to distinguish between the two species of Baccha that were listed by Kloet & Hincks (1976) and "Bacch spp" appears on the card. This is not a problem because only one species, B. elongata is now recognised.

Cheilosia globulipes is no longer believed to be a distinct species, it is now thought to be an aberration of C. urbana (= C. praecox).

More problemmatic are the species that have been split subsequently, but one of the segregates retains the original name:

Anasimyia transfuga was split in 1981 and A. contracta recognised. Since Stubbs & Falk (1983) keys these two species, records of A. transfuga have been considered to be sensu Stubbs & Falk, 1983. It is possible that some early records have not been rechecked.

Platycheirus clypeatus was split in 1991 and P. europaeus, P. occultus and P. ramsarrensis recognised. Although this split was recognised in the second supplement to Stubbs & Falk 1983 (Stubbs, 1996) and a key was included, records have been assigned to an aggregate species unless the observer specifically indicated that P. clypeatus sensu. stricto. was meant.

P. peltatus was split and P. ampluus and P. neilseni recognised. Similarly, records were assigned to an aggreagat species unless the observer specifically noted they had been checked.

The latest checklist checklist (Chandler, 1998) and the second edition of Stubbs & Falk (2002) raise some similar issues:

Cheilosia albitarsis split in 2000 and C. rannunculi recognised.

Heringia heringi split in 2001 and H. senilis recognised.

Platycheirus scutatus split in 1998 and P. splendidus recognised and again in 2002 when P.aurolateralis was recognised.

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